Neutral-position safety control



' July 17,1923 1,462,031

' W. E. DAY

NEUTRAL POSITI-ON SAFETY CONTROL Filed June 30. 1919 I N "ENTO R Wallace E. flay ATTORNEYS Patented July 17, 1923.

UNITED sTATEs PATENT OFFICE.

WALLACE DAY, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOB TO FRANK M. SPENCER,

DOING BUSINESS UNDER THE NAME OF SPENCER ELEVATOR (30., OF SAN FRAN- CISCO, CALIFORNIA.

NEUTRAL-PUSITION SAFETY CONTROL.

Application filed June 30,

To all whom. if m (19 (:(mcemt:

Be it known that I. WALLACE DAY, a citizen of the United States. residing at the city and county of San Francisco and State 01 California. have invented new and useful Improvement in Neutral-Position Safety Controls. ot' which. the following is a specification.

This invention relates to elevators and A articularly pertains to a safety device for mechanically controlled electrically operated elevators. In mechanically controlled elevators which are operated by electricity. such as used for Freight service. considerable (lit iiculty has arisen, due to the fact that the electric supply is often interrupted in its How to the motor and also may be wilfully interrupted by the manipulation of switches at the elevator floors or other safety switches. these switches being manna ly controlled or automatically operated by the movement of the hatchway gates. It will be evident that when the current supply is discontinued. due to any of the foregoing causes. the elevator will stop without retercnce to the operation or condition of the mechanical control mechanism provided tor the elevator. This makes it possible for serious accidents to take place, as. tor example. when the manually operated switch of an electric elevator is left in running position and a temporary interruption oi the motor circuit occurs. a renewal of the current sup-- ply will cause the elevator to travel tor. ards the direction indicated by the switch and in the event that person was entering or leav ing the elevator at the moment oi re-establishment of the circuit an accident would no doubt occur. .t also happens that in safety devices for elevators depending upon grates or doors of the hatchways to complete electric oircuits' when closed, the elevator will start it the manually operated switch has been left in a runningposition. It is also possible for the elevator to he accidentally started when temporary interruption ot' the motor circuit is made due to defects in the mechanism. it is the principal object oi the present invention therefore to provide automatically operating means. whereby it will be necessary for the mechanical controlmechanism to be restored to its neutral position before themotor circuit is placed in condition for further operation, of: the

1919. Serial No. 307,732.

motor and not until the elevator gate and safety switches are closed.

The present invention contemplates the use or a motor-.opcratcd hoisting" set which controlled by a mechanically operated control mechanism, said mechanism being provided with a cable. adapted to be shifted by the operator upon the elevator or floors and furthermore fitted with an auxiliary safety control being: oporatively connected with main contactor and a safety contactor through the operation of which the present ivention is carried out.

The invention is illustrated by way of example in the accompanying drawings, in which the figure illustrates a schematic arrangement ol the control mechanism and the various electrical circuits and contactors connected therewith.

Referring more particularly to the drawings. 10 indicates a source of electric supply adapted to furnish power for the operation of a nxotor 11. This motor is intended to be controlled, by the rotation of a control shaft 12 which is fitted with a cable drum to receive operating cable extending upwardly through the elevator hatchway. 'lhe shatt 152 is normally supplied with controlling cams 1' 1. 15 and 16. The cams 14 and 16 ar direction cams and determine the direction oi" rotation oi the motor while the cam 15 is a make and break cam adapted to complete the circuit of a main contactor 17. The cam l t is provided with a pair of yieldable contact arms 1.8 and 19 which are dis posed upon opposite sides of the cam and are normally held in their outermost posi-- tion and out of contact with the terminals 20 and 21.. The arrangement of the cam 16 is identical with cam 14 previously described. it having contact arms 22 and 23 normally out oi contact with terminals 24 and 25. These two cams are formed with cutaway portions which are disposed upon the same side 0'!" the shaft and are adapted to be moved into register with protrusions 26 upon the contactor arms so that these arms may be collectively swung inwardly to make contact with their respective terminals. The cam 15 is formed with a pair of diametrically opposite recesses adapted to be brought to register with a protrusion 26 upon a contact arm 27 and will when so disposed permit this arm to swing over and.

rest against a terminal 28. The terminal 28 is provided with-a conductor 29 which leads to the positive pole 30 of the source of current supplylO. The contact arm 27 is provided with a conductor 31 which is led to a switch arm 32 of a safety contactor 33, from which point it passes to a terminal 84; adapted to make contact with the switch arm 32 when in its operative position. This terminal is fitted with a conductor leading; to an operating magnet 36 of the main con tactor 1.7. The circuit is completed from the magnet through a conductor 37 to the negative pole 38 of the source of current supply 10. It will be evident from following this circuit that contact of the arm 27 with its terminal 28 is intended to close the main contactor by shifting its arm 39 to make contact with terminals 40 and 41. The arm 39 is fitted with a lead-wire 41-2 passing; from the post 88 of the source of current supply and supplying the terminals 40 and 1-1 with current. The terminal l() is provided with conductor 43. which leads to the field of the motor. as indicated at 44. The opposite side of this field is connected with the positive pole of the dynamo by means of a conductor 45.. The terminal 41 is fitted with a conductor 46 which leads to a connectingwire 47. This wire is secured to both contacts 24 and 25. The contacts 20 and 21 are connected with the opposite pole of the source of cur-.

rent supply by means of a conductor 48.

By manipulation of the switch arm 39. it will be seen that the field circuit of the motor 11 Will be controlled. well the armature circuit. It will. therefore. be possible to determine the direction of rotation of the armature by the direction of rotation of the shaft 12. With this idea. in View, it is common practice to provide a lead wire 49 which passes from the motor brushes to the contact 18 and also is extended to the contact finger by meam; of a conductor 50. It is to be noted that those .constact fingers are upon opposite sides of the control shaft 12. The opposite brush of the motor is provided with a conductor 51 secured to the contact finger 1.) and also connected with contact finger 22 by a com ductor 52. This arrangement is commonly followed in elevator construction.

n order to obtain the objects of the present invention, a safety cam 53 secured upon the .control shaft 12 and is formed with a recess on its circumference which :set at an angle of 90 degrees to the recesses of the make and break cam 15. This recess is adapted to receive a protrusion 26 carried upon a safety contact member which member is adapted to be in engagement with a'terminal 55 when the shaft 12 is in its neutral position. The terminal 55 is con nected with the wire 29 leading to the posi tive pole 30 of the source of current supply. The contact finger is provided with a conductor 56 which leads to one pole of the safety contactor magnet 57. The opposite pole of this magnet is connected wlth a conductor (31 leading to a terminal ()2 of .the safety contactor and adapted to be en gaged by contact member on the end of the switch 32. This member is fitted with a. conductor 63 which connects with the wire 56, and thus communicates with the mag net 57.

Tu operation of the present invention. let it first be assumed that the elevator is at a stop with all of the members in neutral position. as indicated in the drawing. At this time current will pass from the pole 30 of the source of current supply alone the conductor 29 to terminal of the safety control member and thence through the contact finger 54- to the conductor 56. thereafter passing through the coil 57 and to the conductor 58. In the event that the switch 59 is closed. the current will pass through the switch to the conductor 60 and to the opposite pole of the source of cur rent supply. This will complete a circuit through the magnet 57 and will draw the switch member 32 of the safety contactor against the terminals 34 and (52. A circuit will then be established through the conductors (ll to the terminal ()2 along the wire 63 and to the magnet 57. thus setting up a circuit through the magnet. even though the contact member 54 moves from its closed position, as will later be described. .\t the same time an electrical connection will be established through the wire 31, the terminal 34. and the conductor 35. this conductor leading to the magnet 36 of the main coutactor, through which .the current might pass along conductor 37 to the negative pole of the generator. This circuit will not be complete. however, until the switch mom-- ber 27 is in contact with the terminal 28 and the current permitted to flow through the conductor 29 to the positive pole of'the source of current supply. It will thus be evident that by placing the shaft 12 in its neutral position. the safety contactor man; not 57 will be provided with an electric current in the event that the safety switch 59 is closed, otherwise this circuit will. brcompleted upon the closing of this switch. and it will. be furthermore observed that when the switch is closed an independent circuit will be established through the may; net, irrespective oi? the position. of the contact member 5st and the terminal l'Vhen the switch 59 has been cl sed, the shaft may be rotated in either direction to start the motor. ll the control lever oi the shaft is moved forwardly, the motor will rotate in one direction, and if the lever is swung rearwardly, in the opposite direc tion. In either event the rotation oi the shaft 12 a quarter of a revolution will move the cam 15 so that one oi its recesses will register with the protrusion 26 upon the switch arm 27. assuming that the shatt rotated in the direction of the arrow u-, it will be seen that the upper recess ot the cam will swing around to register with the protrusion 26 and that the contact member 27 will engage the terminal 28. t imaltaneous with this movement the contactor finger 27 engages the terminal 29 and the outward movement of the finger 54: will l/lll it) place to break contact with its teriui al The engagement of the member 2? with the terminal 28 will complete a circuit alone the wire 29 from the pole 30 of the source of? current supply, thence through the terminal 28 to the wire 31 and from thence :nong this wire throughthe switch member 32 and the contactor 34: to the magnet wire 35 leading to one pole of the main contactor magnet 36. The circuit will then be continued through the conductor 37 to the pole 88 of the source of current supply 10. This action will energize the magnet 36 and draw "the switch blade 39 against the two terminals l0 and d1. This will act to connect one pole or the source of electric supply with the motor field M: by means of conductors 42, the terminal l0 and the wire 43. At the same time this same pole of the source o'l current sup ply will be connected with the mechanical control device by means of the conductor 42, the terminal ll, the conductor 46 and the wire at? to the two terminals 24 and 25. The opposite side of the field circuit will consist of the conductor 45 leading: to the positive pole 30 of the source of current supply a conductor l8 leading: to the terminals 20 and 21. When the cams have been rotated to the position previously described, the recess of cam 14 will allow the contact finger 19 to be released and to engage the terminal 21 while permitting the contact finger 2?) to be released to engage the terminal 25. This will complete a circuit from the conductor 47 through the terminal 25 and the contact finger 23 through conductors 50 and 4r-9 to the armature of the motor, while allowing; this current to proceed through conductor 51 to the contact finger 19, thence to the terminal 21 and being completed through the conductor 18 to the positive pole or the source of current supply. It will be evident that this action will cause the motor to rotate in one direction and that a re verse operation of the shaft 12 will change the d rection of flow of the current through the armature of motor and thus cause it to move in the opposite direction.

it will now he assumed that the motor is running and that the elevator car is trawling in a predetermined direction. The circuit. through the contactor arm 54: and the terminal will be broken and the magnet will be included in tl e circuit of the conductors 61 and 63. This will act to hold the switch member 32 ol the safety contactor in its operative position. It the current is interrupted either by discontinuance of operation of the source ct current supply or by opening any contactmechanism represented at 59 this magnet circuit will be broken and the switch 32 will fall away from the terminals 34.- and 62. The shunt magnet circuit will be broken by this action, as the connection between the conductors 6'1 and 63 will be interrupted. and at the same time the main contactor maynet circuit will be broken. due to the tact that the circuit through the conductors 31 and P.5 will be interrupted. The motor will then be cut out, irrespective oi the position of the mechanical control mechanism and the various cams carried upon the control sha'tt The contact safety switch 59 may then be reclosed but it cannot establish a circuit as it is included within what might be termed a secondary magnet circuit and will not energizc the magnet 57. It will be imperative, theretore, that before the motor can be started the control shaft 12 must be restored to its neutral position. This action will refrom contact with the move the member 2i terminal 28 and will again establish the pri mary circuit through the sat ety contactor magnet 57 by permitting the contact mem her 5% to engage the terminal 55. hen the safety switch is then closed the magnet 5'? will be re-energized and the switch member 32 drawn against the terminals 35 and 62, thus completing the first oi the main contactor magnet circuit and completing the secondarv safety contactor magnet circuit through the conductors 61 and By the use of the structure here disclosed, it will be insured that the control mechanism must be restored to its normal, neutral position before it is possible for the elevator motor to be started and the direction of rotation of the motor determined. This operation must take place whether the current is interrupted in its flow from the source of current supply, the elevator gates are raised and a circuit broken, a, safety switch 59 manually operated to break the circuit of the magnet 57 or by opening of the safety circuit by means of various safety switches.

It will thus be seen that the device here disclosed, while decidedly simple in. operation and rigidly applicable to elevator equipment in common use will provide the desirable saiety results required and will eliminate all accidents due to carelessness in operation or uncontrollable interruption of the operating circuit.

lVhile I have shown the preferred form of my invention, as now known to me, it will be understood that various changes in the C'Olllbination, construction and arrangement of parts may be made by those skilled in the art, without departing from the spirit of the invention, as claimed.

Having thus described my invention, what I claim and desire to secure by Letters Pat ent is 2- 1. A control system for mechanically operated electrically driven elevators comprising' a uiechanical control member adapted to determine the direction of movement of the elevator, a motor, an electric circuit in eluding said motor and the control mechanism, a main contactor adapted to open and close the motor circuit, a main contactm: circuit adapted to be closed by the operation of the controller, means for rendering the main contactor inoperative and means whereby said contactor will be restored to its operative condition when the mechanically operated controller is moved to its neutral position.

2. In combination with the motor of an elevator and a mechanical controller therefor of the main contactor adapted to be ar tuated' by movement or the mechanical controller from its neutral position to close the motor circuit, a. safety contactor controlling the main circuit and breakingthe circuit of the main contactor when the motor circuit is broken. and means operating in conjunction with the nice ianical controller whereby said controller must be restored to its neutral position before the safety contactor will act to restore the main contactor to its closed position.

In combination With the electric motor of an elevator, a mechanical controller, a motor circuit including the motor and said mechanical controller, a main contactor for closing said motor circuit, electromagnetic means controlled by the movement oi the controller for operating said main contactor, a safety contactor for controlling the main contactor magnetic circuit, a secondary magnetic circuit for controlling the safety contactor, means for establishing said secondary circuit when the controller is in its neutral position, means controlled by the secondary contactor tor maintaining the secondary magnet circuit, irrespective oi? the position ot the controller, and means whereby the accidental interruption of power through said secondary magnetic circuit or the premeditated breaking of said magnet circuit will act to break the main contactor magnet circuit and will render the motor circuit incomplete until the controller has been restored to its neutral position.

1 4- In combination with the hoisting motor of an elevator, a manually operated eontroL let, an electric circuit including the motor and said controller, a main contactor adapted to be actuated by the controller as it moves from its neutral position to close the motor circuit, a safety cont-actor controlling, the main circuit and adapted to break the electric circuit of the main contactor when the motor circuit is broken, and a second electric circuit for controlling the safety contactor, and means whereby interruption of power through said second circuit will act to break the electric circuit of the main cont-actor, and render the motor circuit incomplete until the controller has been restored to its neutral position.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

IVALLACE E. DAY. Witnesses IV. \V. HEALEY, M. E. EWING. 

